AERODYNAMIC INVESTIGATION WITH FOCUSING SCHLIEREN IN A CRYOGENIC WIND-TUNNEL

A flow visualization study was performed using a focusing schlieren sy stem in the 0.3 m Transonic Cryogenic Tunnel at NASA Langley Research Center. The system proved to be a useful flow visualization tool for f lows as low as M = 0.4. This study marked the first verification of th e focusing schlieren technique in a major subsonic/transonic wind tunn el and the first time that high-quality, detailed pictures of high-Rey nolds-number flows were obtained in a cryogenic wind tunnel. This test was part of a development program to implement instrumentation techni ques in cryogenic wind tunnels, with the ultimate aim to use them in t he National Transonic Facility.